Power amplifier and transmitter and the like



J. L. HOGAN 2,249,762

POWER AMPLIFIER AND TRANSMITTER AND THE LIKE July 22, .1941.

Filed Jan. 5,1939 3 Sheets-Sheet 1 July 22, 1941. J. L. HOGAN 2,249,762

\ POWER AMPLIFIER AND TRANSMITTER.AND THE LIKE Filed Jan.'5, 1939 s Sheets-Sheet 2 INVENTOR.

y v J. L. HOGAN 2,249,762

POWER AMPLIFIER AND TRANSMITTER AND THE LIKE- Filed Jan. 5, 1939 3 Sheets-Sheet 3 x A h Law INVEN'IOR.

Patented July 22, 194i renter QFFEQE POWER AMPLIFIER AND TRANSMITTER .AND THE LIKE James L. Hogan, New York, N. Y.

Application January 5, 1939, Serial No. 249,434

4 Claims.

' The purpose of this invention is to provide improvements in series A. C./D. C. power circuits for all Wave band radio receivers, power amplifiers, transmitters, combination and oscillator v circuits, and the like, in which noise is reduced, and in which the different parts may be combined in a common unit.

The invention is a system of radio receiving, power amplifying, and transmitting without static or other noise, with all of the circuits combined in a common unit adapted to be operated by A. C. or D. C. current, and in which are provided, switching devices to cut out the radio frequency and detector units, and cut in a power amplifier as a unit, and also to cut out the speaker and cut in an oscillating tube and circuit for transmitting, and in the system is also a multiunit line rectifying tube, and a plurality of multielectrode heater type tubes in series with each other and the rectifying tube.

Many attempts have been made to improve receiving, amplifying, and transmitting apparatus. Such apparatus has been provided in different types and designs, but a single compact unit has not been produced which successfully combines receiving, power amplifying, and transmitting apparatus that eliminates static and noise, and although devices in some patents and in use have resistance coils that may be used for series A. C./D. C. power circuits, these have not, up to the present time, been used in apparatus except for receiving, and in order to make the parts operate successfully in combination it has been found necessary to provide amplifier and power output tubes with their own filters and resistors in their cathode circuits.

In this combination it is also necessary to provide every possible precaution against noise, static, and hum, and therefore the cathodes of the tubes are connected to the chassis through resistors and condensers and the power supply wire.

One object of the invention is to provide a power circuit which can be employed for transmitting, which will have a low current consumption, which will operate without producing internal static, and which will generate pleasing sound wave creating impulses.

Another object of the invention is to provide an improved power circuit which can be constructed with a minimum number of parts and elements, and which can be utilized for transmitting and the like, and which will also operate without generating static disturbances.

Another object is to provide an improved series A. C.D. C. power'circuit by which it is possible to impress a high voltage upon the plates in the tubes of a vacuum tube circuit in which it is connected to boost amplification and rectifi- 5' fcation.

I Another object of the invention is to provide a power circuit with cathode elements so arranged that the heating effect is produced more efficiently and with less time lag, and may be obll'liltained in its fullest extent.

Another object of the invention is the provision of a power circuit with an improved system of cathode elements and condensers, so arranged that regeneration may be eliminated, and long a distance reception or transmitting obtained without fading and Without static, and the volume obtained greatly increases, without reducing the supply current of the proper kind to the units of a radio receiving or transmitting circuit re- -gardless of whether it is connected with a direct or an alternating current source of supply' Still another object of the invention is to pro vide in a power layout employing a coupled transformer andrectifier, in which the possi- "bility of burning out the windings of the transformer will be avoided.

And a still further object is to provide a combination receiving, amplifying and transmitting n? circuit and the like which is of a simple and economical construction.

With these ends in view the invention embodies a receiving, amplifying, and transmitting unit comprising line rectifying, radio frequency amplifying, detecting, audio amplifying, push-pull amplifying, and oscillating tubes in which the elements thereof are connected in suitable circuits with the cathodes of the tubes individually connected to the chassis through resistors and con- 45 densers, and in which parts of said unit may be used for receiving, other parts for power amplifying, and other parts for transmitting.

Other features and advantages of the invention will appear from the following description, so taken in connection with the drawings, whereint- Figure 1 is a diagrammatic View showing the group arrangements of the cathode, heating, and

other elements in connection with certain con- 5.3 densers and variable connections in combination Another object of the invention is to providereceiving, power amplifying, transmitting, and oscillating circuits.

Fig. 2 illustrates push-pull oscillation and boost high voltage amplification and rectification.

Figure 3 shows another series A. C./D. C. high voltage amplification and full wave rectification power circuit and shows a resistor and condenser in each cathode circuit, for transmitting and the like.

In the drawings typical circuits are illustrated wherein the parts of a receiving unit are shown within the bracket I, extending from point I to point 2, the parts of a power amplifier circuit within the bracket 2, extending from the point 2 to the point 3, and those of the transmitting circuit within the bracket 3, extending from the points I or 3 to the point 4.

The device is connected in an A. C. or D. C. circuit by a plug 4 which has wires 5 and 6 leading therefrom with the wire 5 connected to a line switch 1, the opposite terminal of which is connected to wires 8 and 9, and the wire 9 is connected to the chassis through a filtering condenser This switch 1 is used to cut in the power house current. The wire 8 extends to plate II and is connected by a wire l2 to a plate 13, both of which plates are positioned in a rectifier tube 4. The wire 5 is also connected through a resistor l5 to a cathode heater 16 in the tube I4, and this heater is connected .to a heater I! in the oscillator tube by a wire l8. and from this tube to a heater I9 in one of the push-pull amplifier tubes by a wire 20, and then to a heater 2| in another push-pull amplifier tube, by a wire 22.

The heater 2! is connected to a heater 23 in the audio amplifier tube by a wire 24, and this is connected to a heater 25 in the detector tube by a wire 26, and from this to a heater 21 in the radio frequency amplifier tube by a wire 28, and the heater 2'! is connected to the chassis by a wire 29 to the chassis at the point 30.

The cathode 33 of the tube 14 is connected to a wire 34 which conducts the rectified output of the tube l4 through a filter 35 to a positive B. supply wire 36 when A. 0. current is used. A

two point switch is provided, which has a contact 31 that may be moved to engage a contact 38 for unlimited power house D. 0., 13., when the device is on D, C. power, thereby cutting out tube l4.

Each of the cathode circuits of the tubes is connected to chassis through a condenser and a resistor, the connection of the cathode 39 having a condenser 40 therein with one terminal of the condenser connected to the cathode and the other to the negative 3., and with the cathode also connected to one end of resistor 4| with the other end thereof connected to a variable resistor 42, the opposite end of which is connected to the grid 43 of the tube 44.

The variable arm 45 of the variable resistor 42 is connected to the wire 6 providing double volume control and cathode biasing for the control grids of the tubes. The cathode circuits of the tubes include condensers and resistors, and the numeral 45 indicates a condenser and resistor unit of the cathode 41 of the detector or amplifier tube, and 48 a similar unit of the cathode 49 of the audio amplifier tube. The cathodes 50 and 5| of the push-pull amplifier tubes are connected through a resistor 52 to the chassis through a common negative B, and the cathode 53 is di-' rectly connected to the chassis. The cathodes may also be provided with suppressors which may be connected to the cathodes at their sockets.

There are many circuits of various types and designs, however, in this the aerial 54 is the signal input and this is connected to a condenser 55 which is'connected to a primary winding 56 of a transformer, and from the primary Winding to the chassis at the point 51, and the secondary winding 58, by inductance, takes the impulses to the intake control grid 59 of the radio frequency amplifier, the control grid being tuned by a condenser '60. One end of the winding 58 is connected to the stator of the condenser 60 and also to the grid 59, and the opposite end of the Winding is connected to the rotary of said condenser and also to negative B. The primary winding Bl of another transformer is connected, at one end, to a plate 62 of the radio frequency amplifier tube, which is indicated by the numeral '63, and at the other to the positive B through the supply wire 36, and also to the screen grid 64, of the tube, and this is also connected through a resistor 65 to the plus B through Wire 36. The inductance winding 66 of the transformer takes the amplified sounds from the plate 62 to the input control grid 61 of the detector tube 68 which is tuned by a condenser 69. One end of the winding 66 is connected to the stator of the condenser 69 and also to the grid '61, and the other to the rotary of the condenser and to negative B. The audio amplifier tube 44 is known as resistance coupled.

The tube 68 is also provided with a resistor H3, one end of which is connected to the condenser H, which is a .00025, and this end is also connected to a plate 12 in the tube 68, the other end being connected to plus B through wire 36,

and the other end of the condenser is connected to negative B. Another resistor 13 is provided with one end connected to plug B through wire 36, and the other to the screen grid 14 of the tube 68, and also to the negative B through a condenser 13A are a 50,000 ohms resistor. The connection between the resistor 10 and plate 12 of the detector tube 68 is connected to a contact A of a three point switch 15, the arm of which is connected to the control grid 43 of tube 44 and in this connection is a condenser 16, and it will be noted that with the arm 15 engaging the contact A the tube 44 will be working as a first audio amplifier.

In the push-pull amplifier tube circuit is a transformer, the primary winding Tl of which is connected to plus B at one end, through the transformer, which is of the push-pull type and indicated by the numeral 18, and then to a plate 19 in the audio amplifier tube 44 at the other, the plate 19 being the amplified output of the tube. A resistor is provided, one end of which is connected to screen grid 8| in the tube 44 and the other to plus B. A similar grid 82 in one of the push-pull amplifier tubes is also connected to plus B at this point. The winding 11 of the transformer supplies, by inductance the plate to grid coupling to the secondary winding 83 of the transformer 18 which supplies the sounds to control grids 84 and 85, the said grids being connected to each end of the winding 83 and the said winding 83 being tapped at the center and connected to negative B through a resistor 86. The plates 81 and 88 of the push-pull amplifier tubes are connected to the central points forming the intermediate terminals of a double throw switch 89, and when the contact bars of the switch engage terminals 90 the said output passes through a push-pull primary Winding of a transformer 92, one of said terminals being connected to one end of the winding and the other to the other, and the winding is tapped at the center and connected to plus B. This primary winding 9! supplies the power audio output to the speaker winding 93 by inductance.

One of the novel features of the device is that by turning the switch so that the arm will engage a contact B, a microphone may be plugged in at T and T1, and the device is converted into a public address system to amplify sounds, voice, records, or telephones. The circuit is provided with a microphone transformer 94 one end of the secondary winding of which is attached to negative B and the other works through the condenser 15 to be amplified through the detector tube 44, and. then through the power tubes 95 and 96 to the speaker 93. The primary winding 91 of the microphone transformer 94, is connected at one end to negative B and at-the other to batteries 99 that supply the microphone. 15 may be turned to engage the contact C thereby connecting to the terminal T2, and this may be connected to the detector tube of any radio receiver for greater power output, and T1 and T2 may be attached to any phonograph attachment for a greater output.

Another novel feature is that by turning the arm of the switch 15 back to the contact B and the switch 99 to the terminals 99 the device will function as a transmitter working through the tube 44 and the power amplifier tubes 95 and 95 to the oscillator control grid I93 which is 'supplied through the condenser or crystal oscillator I09. The output of the tubes 95 and 9.5 is connected to one end of a coil Iiil and the other end is connected to plus B through a resistor I92. The control grid I99 is also connected to one end of a coil I94 through a trimming condenser I95, and the plate I95 and screen grid I91 of the oscillator tube I98 are tied together at'the socket and connected to the other end of the winding coil I94, which is tapped at the center and connected to plus B. The stator of condenser I99 is connected to the grid end to the winding I94 and another stator to the plate end of condenser I95, and the rotor is connected to chassis and plus B through another condenser H9 and cathodes 50 and 5|. Another coil I i I takes the power output to an aerial H2 and the opposite end of the winding may be connected to the chassis as shown at I I IA or left loose.

And another novel feature is that the transformer 18 controls the transmitted output in K. C., the K. C. being (on the spot) at what the transformer is built for or happens to be. The condensers I99, I59, and I95 are for neutralizing the oscillator grid I03 and the plate I99 and this tunes to frequency of the transformer 19. The control grid I93 is connected to negative B through a resistor I I9, and the screen grid I I5 of the tube 95 is connected to plus B.

In operation each element and unit, being connected to its proper potential, and with the plug 4 connected to a source of A. C. or D. C. current and with the switch 3I closed, current will flow through the wire 5, and through the system to the wire 6, passing through the heaters 21, 25,23, 2I, I9, I1, and I6, and through the resistor I5 to the line 5, the said heaters being in series with each other and with the resistor and lines.

In the design illustrated in Figure 2 the circuit of the power supply unit includes a full wave rectifier tube H6. The numeral H9 designates a transformer of the iron core type having The arm 7 III a primary winding I29 and a secondary winding I21 and the ends of the secondarywinding are connected to the two elements I I1 of the rectifier H5, and at the center of the winding I2I is a tap I22 which is connected to the chassis of a vacuum tube set with which the power unit is connected. The transformer H9 is provided with a winding I23, each end of which is connected to the heater I I9, and this winding supplies filament or heater current for the rectifier.

A device for changing the circuit from A. C. to D. .C- or. :from .D. C. to A. C. is shown at I24, and this is formed with a'core I25 in a coil I29 and as the coil is energized it will drawthe armature I21 toward the solenoid formed thereby. One end of the coil is attached to the armature and the other through a wire I28, which has a chassis connection with a condenser I29 therein, and which is also provided with a power current switch I39, to a plug I3I which may be plugged into a current supply which may be either A. C. or D. C. The armature I21, when the coil I25 is not energized, engages a contact which is connected to the primary winding I29 of the transformer H9, and the other side of this: winding is connected to the negative return wire 5 corre-' sponding to a similar wire in Figure 1, and which is the negative intake for the filaments or heaters and is the plate supply for D. C. current. This wire is connected to the chassis at I29A and I293 makes chassis negative.

The numeral I32 designates a filtering choke and I33 the usual filtering condensers, and one end of the coil or winding of the choke I32 is connected to a filtered A. C.-D. C. plus plate supply wire I34 and this has a test outlet I35 therein. The other end of this winding is connected by a wire I 36 to the heater element II 8 of the tube H5, the rectified A. C. output. A wire I91 which is plus plate supply on D. C. is connected to the wire I36, and has a terminal I38 positioned for engagement by the armature I21 when the coil I26 is energized by D. C. current. When the armature is infiuenced by the solenoid it not only engages the terminal I38 but also engages the terminal I39 which is connected to the resistor I5 and also to a double pole single throw switch I49. On A. C. current a spring I4I holds the armature I21 in engagement with contact points I42, at which time the resistor I5 supplies the heater currents to the heaters 21, 25, .23, 2|, and

I9, as in Figure 1.

By contacting the terminals 99 with the switch 89 and closing the switch I49 a higher powered transmitter is provided. The power may be increased or decreased by using diiferent types of tubes and may be controlled by the variable resistor arm 45. A resistor I43 in a connection from the switch I to a heater I44 supplies the heating current to the heaters I44 and I45 of the oscillating tubes I46 and I41, and a wire I48 supplies the plate current through the switch I49.

A push-pull interstage transformer I49 takes the amplified output of tubes 95 and 96 by wires I50 and I5I to each end of the primary winding I52, and this is tapped at the center and connected to plus B through test outlet I 53.

The ends of the secondary winding I54 of the transformer I49 are connected to control grids I55 and I55 in the tubes I49 and I41, and this winding is tapped at the center and connected to negative B through a resistor I51. The cathodes I58 and. I59 of these tubes are joined together and connected to negative B through a resistor IGIl, and the plates IfiI and IE2 are connected to. the screen grids I53 and I54 at the sockets and the grids are connected to each end of the winding I65. The oscillator winding I65 is tapped at the center and connected thereby to a plus B current through a test outlet I65, and the plates IGI and I52 are connected together through a condenser I61, and in addition to this the plate IBI and the control grid I56 are connected together through a condenser I68, and the plate I62 and the control grid I55 are connected together through a condenser I59. The grids I55 and I56 are also connected together through a condenser I and to negative B, in the connection of which is a condenser I1! and cathodes 58 and 59. These condensers I61, I68, I69, and I1!) are neutralizing and tuning condensers, and the transformers 13 and I 49 fix the K. C. in the output winding I12 and the condensers tune to that. That is type 6L6 tube and a 60 watt output is good for type 100th tube also. With these parts a combination radio receiver, a power amplifier and a transmitter maybe built on a 6" x 11" x 2" chassis. The other wires and units of the power circuit are the same as in Figure 1 and therefore the same reference numerals are used. The end I12A of the winding I 12 may be connected to the chassis through a condenser as shown or may be left loose.

This type of power is illustrated as being in a combination circuit for receiving radio signals, power amplifying, transmitting and oscillating but it will be understood that it may be used in other types of circuits, and also that this type of combination circuit may be operated by transformer and batteries power parallel Wired. In operation, with the plu I3I inserted in an outlet or connected to a source of current, and with the switch I closed, there is only one knob to ter of the same program.

The diagram shown in Figure 3 is similar to that shown in Figure 2, with parts omitted, the plug I13 being similar to the plug 4 and the current shifting device I14 being similar to the device I24, likewise in this design the cathodes of the tubes are individually connected to the chassis through resistor and condenser. A resistor I15, similar to the resistor I5 is in the circuit I16 to the heaters I 11, and the cathodes I18 are connected to chassis through condensers I19 and resistors E80. A transformer I8], similar to the transformer H9, is also provided with the secondary winding also connected to the plates of the line rectifying tube I82. This circuit may be used independently or in combination with the parts shown in Figures 1 and 2 as may be desired.

It'will be understood that other changes may be made without departing from the spirit of the invention. One of which changes may be inthe use of any number of tubes in the set instead of the number shown, another may be in the use of other means for connecting the individual parts, another may be in the use of any other means for shifting from one current to another, and still another may be in the use of filters or resistors of any other type, or in the use of other devices in the place of or in addition to any of the parts.

The construction will be readily understood from the foregoing description. In use the tubes, transformers, condensers, resistors, and other parts may be arranged in a relatively small compact casing and, as hereinbefore described, parts may readily be selected for receiving, other parts for amplifying, and other parts for transmitting. It will be understood, however, that this unit, or any parts thereof may be used for various types of radio apparatus, or for any purpose.

Having thus fully described the invention what I claim as new and desire to secure by Letters Patent, is:

1. A circuit arrangement of the class described, including a signal input circuit, an audio amplifying circuit including an audio amplifier vacuum tube, a push-pull audio amplifying circuit including audio amplifying tubes and a transformer, a loud speaker, means for controlling output of the first audio frequency amplifying tube whereby the output of the push-pull audio frequency amplifier may be controlled, an oscillator vacuum tube, an oscillatory circuit for said oscillator tube, and including a coil, an oscillatory circuit for the push-pull amplifying tubes and including a coil and the secondary of the push-pull amplifying transformer, an output circuit inductively coupled with the coils, a rectifier vacuum tube for supplying high tension current to the oscillator and amplifying vacuum tubes, and switch means operative in one position for connecting a loud speaker to the push-pull amplifying tubes and in another position for connecting the pushpull amplifying tubes in the oscillatory circuit for exciting the oscillator tubes and thereby controlling the output of said oscillator tubes.

2. A combination of elements as recited in claim 1, including a low resistance, a high milliampere speaker field connected in the rectified output, coils of said transformer being of the radio frequency and audio frequency type having the outside end of said secondary coilconnected to the control grids and the intermediate terminal of the secondary tothe chassis, and the primary outside end connected to the plate with the inside end to the positive terminal of said source of current.

3. The circuit arrangement as in claim 1, with a multi-point switch, including a movable contactor, normally set on one of its points for broadcast signal reception through said signal input and audio amplifying circuits to said loud speaker, a second transformer having its secondary connected between another of the switch points and said chassis and its primary between the latter and one of a group of pickup circuit terminals, an intermediate terminal of said group being connected to said chassis and a third terminal of said group to a companion point on said switch, the movable contactor of said switch being connected through a condenser to the grid of a detector-amplifier tube constituting a stage of said push-pull audio amplifying circuit, and a local power supply in circuit with said primary, said group terminals being adapted for the interchangeable connection thereto of transmitter instrumentalities for the conversion of said circuit arrangement from use as an all wave band broadcast receiver to use as a transmitter of signals from said transmitter instrumentalities between said pickup circuit and said detectoramplifier tube, an all wave band broadcast signal output circuit, the first named switch means being operable to connect the output end of said push-pull audio amplifying circuit to said loud speaker when said signal input circuit'is operative through said multi-point switch and also to connectsaid push-pull audio amplifying circuit to said broadcast signal output circuit when said pickup circuit is operative through said multipoint switch. 7 7

JAMES L. HOGAN 

